The present invention generally relates to skid-steers loaders commonly found and employed in the construction industry, and that have a cabin which is accessed through an opening having a protection or safety door. Such skid-steer loaders are also sometimes commonly referred to as skid-steers or skid loaders. These machines have a variety of uses in agriculture, landscaping, and construction and are produced by industrial equipment companies such as Bobcat, Caterpillar, Case, Clark, Ingersol-Rand, New Holland, among others.
Commonly, a skid-steer loader is a machine that consists of a base on four wheels, with a forward cabin enclosure for the operator. The operator, when seated in the cabin, operates a pair of independent travel controls for permitting essentially zero radius turning by independently controlling motion of left and right wheels or tractor belts—the skid-steer.
Commonly, a loader assembly is pivotally attached to skid-steer. The loader assembly commonly comprises a pair of hydraulically controlled lift arms that are pivotally coupled to the frame of the skid-steer at one end, and are intended to move in unison about a defined base pivot axis generally rearward of the cabin. A hydraulically controlled tiltable bucket, or other implement, is commonly pivotally attached and between the other end of the pair of lift arms.
The arrangement of the loader is such that the lift arms are capable of moving in planes parallel to the sides of the machine, and pivot around the base pivot axis to the rear of the machine. These lift arms are intended to move in unison about this base pivot axis so as to raise and lower the attached bucket or other device that is attached to the ends of the lift arms in front of the operator's cabin.
Within the cabin are independent controls for independently controlling the hydraulically controlled tiltable bucket about an implement pivot axis at the end of the lift arms, and hydraulically controlling the lifting movement of the pair of lift arms by movement about the base pivot axis.
One of the inherent risks of the current commonly accepted design of the skid-steer is related to the lifting mechanism of the loader assembly—namely the pair of lifting arms as described above. Some models of this machine include a cabin with an access door through which the operator must enter and exit the skid-steer cabin. Although the arrangement of the lift arms and associated cross members may take on many forms, the arms or cross members may transversely pass through a portal through which an operator may pass through to access the cabin. The presence of the door, either front mounted or side mounted, in conjunction with unwanted movement of the lifting arms presents a potential risk for damage to this door and/or the safety of the operator entering or exiting the skid-steer cabin.
The risk for damage to the skid-steer cabin is that if the cabin door is open and the lift arms of the skid-steer are raised or lowered, these arms could potentially damage or destroy the cabin door. An additional safety hazard present is that if this door is open and the operator is attempting to enter or exit, serious injury or death may result if the arms unexpectedly move across the door opening. Similarly, a bystander may attempt to open the cabin door unaware of the hazard of movement of the lifting arms thereby potentially placing the bystander in harms way.